Alexander Hamilton, the first secretary of treasury of the United States, publicly endorsed Thomas Jefferson (Aaron Burr's competitor), leading to Jefferson's presidency. Wanting a democratic republican for a vice president, Jefferson reformed the party to get rid of Burr, with the argument that it didn't make sense to have the runner-up become the vice, seeing as the two individuals would have differing views on political, social, and economic issues.
"A. The English king made claims to the French throne" is a reasonable answer but it should be noted that the origin of this war is very complex and many people are still guessing.
